Even so, I've never been to any event where a tech or any track official made people take center caps off or even make mention of them.

Right, because you put your signature on that paper and they trust you. I'm not here to debate whether it's a big deal or not since I'm sure everyone has their own opinions regarding that. I just wanted to point out that, as a technicality, people are asked to remove them on the tech inspection that they sign.